Device for the manufacture of metallic protecting tubes



Aug. 11, 1925.

A F. ZACHHUBER DEVICE FOR THE MANUEACTUEE OE'EETALLIG PEOEECTING TUBES Filed Feb.y e. 1923 5 Sheets-Sheet iarney Aug` l1, 1925. 1,549,403

- F. zAcHHuBER DEVICE FOR THE MNUFACTUREv 0F METALLIC PROTECTING TUBES Filed Feb. 6. 1923 3 Sheets-Shed'I 2 Aug. 1l, 1925.

F. ZACHHUBER DEVICE FOR THE: `MANUFAC'I'URE oF METALLIC PROTEGTING TUBES Filed Feb. 6. 1923 3 Sheets-Sheet 3 frz V arezzo?1 112.27722 Zac/zzer' Patented iAug. y1l, 1925.

UNITED STATES PATENT OFFICE.

-FRANZ ZCHHBER, OF AMBEBG, GERMANY.

DEVICE THE MANUFACTURE F METALLIC PROTECTING TUBES.

Application led February .6, 1923.. Serial No. 617,394.

To all whom it may concern:

Be it known that I, FRANZ ZACHHUBER,

a citizen of the German Re ublic, and a resident of Amberg, Bavaria, erman have invented certain new and useful limprovements in Devices for the Manufacture of Metallic Protecting Tubes, of which the following is a specification.

This invention relates in general to a dcvice for the manufacture of metallic protecting tubes for use in connection with` the laying of electricwires, and in particular to a `tube drawing tool with the aid of which,

while the wires are being-laid, a strip of sheet metal is transformed into a tube surrounding or enclosing and protecting the laidwireor wires. In particular this invention relates to improvements in devices of this kind which are known per se, but

are possessed of certain ldrawbacks which are. overcome by this invention. First of all an unobjectionable tube is produced by a speciallyy suited configuration of the mouthpiece and by a specially provided tubular guide at the delivery end of that device. This tube is distinguished by its overlapped seam and leaves the tubular mouth piecev as al straight tube which neither unwinds, nor has a tendency to turn 'around its longitudinal axis similarly to the threads ofa screw.

.Besides, the comparatively great resistance experienced with tube drawing devices withA stationary preliminary drawing cheelm when drawingor shaping the sheet metal tube, and to be overcome y an increased expenditure of power, is. obviated by using aspre-v liminary drawing device a .rotary air of rollers, of which one is practically o spherical shape and which both serve also for the ,preliminary rounding of the sheet-'metal strip. These rollers, although being subject to pressure and doing also the preliminary drawing work, unroll easily along the sheetmetal strip pulled through between them and insure, besides, a good guidance therefor along the middle of its length, thereby preventing lateral displacement and making the strip enter the mouth-piece always in right position.

'Generally one pair of rollers will do, but, if desired, or necessary -in particular cases, two or even more maybe arranged in succession.

It is suited .to'thepurpose-'to provide the spherical roller Awith .a circumferential groove which receives, or through which so that the strip which is bent preliminarily by the members eecting the preliminary drawing is transformed into a'tube without any trouble and in accurate position relatively to the wires which are enclosed thereby. The wircs'are thus, where a circumferential groove, as mentioned, isprovided, inserted immediately at the rollers, whereas, if there is no such oove, the wires can be insertedonly behin lthe rollers or between them and the drawing 'mouth piece.

My invention is `illustrated, by way of example, inthe accompanying drawings,in

is a longitudinal section therethrough; Fig. 3 is aside view thereof; Fig. 4 is a separate view solely of thedrawing mouth piece, in longitudinal section; Fig. 5 .is a rear` or inner or edge view of said mouth piece; Fig. 6 is a .transverse section through. the mouth piece, drawn on a larger scale; Fig. 7 is a separate view of the pair of rollers, the transverse section of the casing forming lateral members lying in line A -B 'of Fig. 3. Fig. is a transverse section in line C-D of Fig. Sand shows the guide means for the sheet metal strip. Fig. 9 is an illustration similar to Figs. 4 and 5 and shows a modification of the drawing mouth piece; Figs.-

10, 11 and 12 are transverse sections through this modified mouth iece in the lines E-F,

G--H and J-K of ig. 9, drawn on a scale similar to Fig. 7 showing a modification of the spherical roller; Figs. 14: and 15 are similar illustrations showing also modifica-v tions of therollers.V

The device or .tool consists of a frame l f composed of sheet-metal members and provided at its rearend with a handle 2. The sheet-metal strip intended to be transformedinto a tube is coiled-as shown at 7, Figs. 1

and 2this coil being supported by -a pin or which Fig. 1 is a plan of the device; Fig. 2

spindle that is removable-1n order to receive 100 like that of Fig. `6.l Fig. 13 is an illustration another coil if the preceding one has been worked up. The strip 7, runs through two parallel guide membersV 3, Figs. 1, 2 and 8, which are 'ded by a transverse pin and through which passes a screw-threaded spindle having a right-handed and a left-handed thread bywhich the distance between the guide members may be varied, i. e. adjusted to the breadth of the metal strip 7.

There then follows, in the direction to the mouthpiece, the two rollers 4 and 6, Figs. 1 to 3 and7, which are carried by pins Supported .in the frame 1, and of which the roller 4 is practically spherical, whereas'the roller 6 has a circumferential shape corresponding to the shape of the roller 4. This roller is held in place not solely bythe lateral frame members, but also and chiefly by two lateral members 12 which are longitudinally slotted and are arranged obliquely with respect to the frame and are each under the pull of a coiled spring12 secured at one end to the respective member 12 and at the other'endto a pin 12b rojecting forth from the respective side of t e frame through the slot 12. The laterally projecting parts of the members 12 form bearings forthe axle 4a of the, spherical roller 4, and this axle is ulled by the springs 12n into hook-like 'pro- ]ections 1 of the lateral frame members 1, as visible especially in Fig. 3. It.4 1s therefore possible to draw the axle y4*? with thev roller 4 out of said hooks 1a and to.swing the parts 4 and 4a` around the ins 1-2b so as to move the roller 4 out ofan away fromthe roller 6. A f v '8, Figs. 1 and 2, is a lubricatin cushion for the metal strip 7 that passes a ong over `i it on its Way from the pairof rollers to the mouth-piece, as illustrated lin Fig-2. y The metal strip 7 passes .from 1the j` coil 7 throughbetween the guide members v3 to the "rollers 4 and 6 between. which it is preliminaril bent. At the same time the wires 13 tive y strip, thework of enclosing the wires in the lare introduced into -the"groove `5 of the spherical roller'4, as wellv as into' the channel-shaped metal strip'7 (Fig.2)', the latter gliles lthen over the lubricatin fcushion 8 an 11, in which the preliminarily `bent or roundedstrip is turned into atube, the rims of which overlap one another,-as shown in Figs. 5 and 6.

As the groove 5 o the roller'4 forms aced into the preliminarily bent metal ri holdin to each guide for the wires while these are introu st them in proper position relaother, as well 'as' to the bent protective tube is done in mo'st. satisfactory manner, requiring no particular attention of the workman.

Anyhow, it is not indispensably .requisitegets into the drawing mout piece 9 to "metal channe pletely prevented from distortion, the' overmageos use a complete spherical roller, such as 4i Fig. 13, the wires being in this case placed into the metal strip on y afterI it has made its Way through between the rollers and has been preliminarily bent to form a channel, as described. The roller 6b, Fig. 13, is practically such a one as the roller 6 of Fig. 7.

The roller pairs 4- 6, Fig. 14, and 4d-6d, Fig. 15, are not two modifications, but are intended to be used simultaneously, that is to say, they form arts of one device in which they act one ater the other, the sheetmetal strip being rst acted on by the rollers 4c and 6 and then by the rollers 4d and 6d. It is a matter of course that in the case of two pairs of rollers the device is correspondingly longer. Each pair is arranged and supported exactly in the manner illustrated in Fi l and 3, especially as regards the slotte members 12, the springs 12, and the' hooks 1.' Eecting the preliminary bending 'in two stages facilitates this procedure, also as regards the closing of the channel to form the protective tube. The co-operation of the two pairs of rollers with the drawing mouth piece is just the same as in the irst case. The metal channel arrives at the mouth-piece in position to be properly closed during its passage therethrough, the rims overlapping one another.

The drawing mouth piece 9, Figs. 1 to 4, is exchangeable; it is held in place by a kind of clasp 10 attached to the frame ot the tool, and has a longitudinal guide groove 14 extending veither through the' entire length of the mouth piece or' disappearing finally as inthe modification illustrated in Figs. 9 to 12 in which a comparison of Figs. 10 and 12 shows that the orifice of the drawing mouth-piece (plane .1 -K, Figs. 9 and 12) is perfectl clrcular, the overlapping rim of the ytubu ar strip forminpart of the circle, in V`contradistinction to lgs. 5 and 6 Where the overlapping rim lies outside of the circle.

The end of the tool is formed by a piece of ftube^11 which is arranged at a certain obtuse angle with respect to 'the longitudinal axis of the frame of the device or tool.

The guide groove 14 guides only one of therims or edges of the metal channel 7, the other rim lor edge being free to move round within the mouth piece so as to aproach the guided rim or edge and underapping it, .as shown in Figs. 5- and 6, as 4well as in Figures` 10 to 12. Owing 'to the being thus guided, itis comapping appearing as a straight line. It the guidev gfoove 14 terminates before the orice of t Figs. 9 and 12'-, the overlapping rims are pressed against one another, that i'sto say, the outer rim is pressed against the inner,

the outer diameter of the finished tube being SEB e drawing mouth piece, as in ,i

then eractly egual to the diameter of the orice ofthe mouthpiece (Fig. 12).

In view of the fact that a certain inner` tension' arises in the metal strip, or metal v straightening. To obviate this, rthe angularly arranged outlet tube 11 is provided, the effect of which is, as practical experience has shown, that the finished tube remains perfectly straight, there being no tendency to bend or curve after it has been forced l through the obtuse angle existing between that outlet tube piece. I

The frictional resistance arising during the passage of4 the metal strip `through the device is considerably reduced by the preliminary bending members being rollers, such as 4 and 6, as well as .4b and 6", 4 and 6c, and 4d to 6, there being rolling friction instead of liding friction; and the resistance is sti more reduced if the tube is closed already inthe drawing mouth piece,. as in Figs. 9 to 12 instead of only in the outlet tube 11, as in 1 to 4.

I claim f 1. A tool for 'transforming sheet-metal' and the drawing mouth strips into protecting tubes for electric wires while laying the latter, comprising, in combination, a practically spherical roller; a correspondin ly shaped counterpart therefor; means or supporting a coiled sheet-r metal band located in frontof said roller and its counterpart; and a drawing mouth piece located behind the said roller and its counterpart as regards the direction of motion of the sheet-metal band during its passage through thedevice, and having a guidegroove for one of the rims of the metal band,` said groovel having a slight lateral tuin on its way from its one end to its other en 2. A tool for transforming sheet-metal strips into protecting tubes for electric wires while laying the latter, comprising, in c mbination, a practically spherical `roller; a correspondin ly shaped counterpart therefor; means or supporting a coiled sheetmetal band located in front of said roller and its counterpart; and a drawing mouthpiece located behind the vsaid roller and its counterpart, as regards Vthe direction of motion ofthe sheet-metal band during its passage-.through the device and having a guide groove for one of the rims of the metal band,

said groove having a slight lateral turn on its way from its one end to its other end but ending` somewhat before the orifice of said mouth-piece so as to let this orifice be circular, for the purpose set forth.

3. A -tool for transforming sheet-metal strips into protecting tubes for electric wires While laying the latter, comprising, in combination, a practically spherical roller; a correspondingly shaped counterpart therefor ;l means for supporting a coiled sheety metal bandlocated vin front of said roller and its counterpart; a drawing mouth-piece located behind the said roller and its counterpart as regards the direction of motion of the sheet-metal band; and an outlet tube attached to the end of said mouth-piece and being located at an obtuse angle with respect thereto, substantially'and for the purposes set forth.

In testimony whereof I ailix my signature in presence of two witnesses.

yFRANZ ZACl-IHUBER. Witnesses: A. C. I-IoUGH'roN,

Annxr Pmnrrrorr. 

